The preservation of raisins in storage and packaging has always been a concern. Airtight or moisture retentive packaging is generally used to address this concern, but the problem is often heightened considerably when the raisins are combined with other food ingredients which are relatively dry and moisture absorptive. Thus, raisins combined with such food stuffs as cereals, flours or dry mixes, or baked into such preparations as breads and cakes in packaging which may be opened and reclosed several times during use, create an ever present concern for preservation of the quality of the raisins. When raisins begin to dry out, they undergo a deterioration in taste and mouthfeel, making them less palatable and therefore less appealing to consumers.
The use of humectants such as glycerol and sorbitol is disclosed by Fulger, et al., U.S. Pat. No. 3,952,112 (Apr. 20, 1976) and U.S. Pat. No. 4,103,035 (July 25, 1978). Glycerol is the humectant of choice in these disclosures. Glycerol is less than fully satisfactory, however, since it is not a natural food ingredient and lacks a natural food flavor. Glycerol in fact has its own taste which it imparts to the raisins, replacing or masking the raisins' natural taste.
It has now been found that the textural quality of raisins can be retained, with no loss of the natural raisin flavor, in environments which would otherwise cause a loss of these qualities, by elevating the ratio of fructose to glucose above that naturally inherent in raisins without lowering the total sugar content, and that such elevation can be achieved by a process involving blanching, infusion, tempering and drying under controlled conditions of temperature and time. The result are raisins with all natural ingredients and with the well known and well liked raisin taste, plus the ability to retain both this taste and the soft texture of fresh raisins in moisture absorptive environments.